I just let my MFM subscription lapse. It sounds like it should be a good mag for marine only but it blows. There are almost no photos. The editing is terrible. I wonder if they have even heard of a word processor. They certainly do't use spell check. They have alot of beginner articles but much less for more advanced hobbiests. I recently went through my stack of MFM and Aquarium Fish magazines prior to a move, tearing out articles to save to reduce the volume. I saved quite a few from AF but after not finding a single article I thought was worth saving in the first year of MFM mags that I went through I just dumped the whole stack into the recycling.
I wish I had a true recommendation for you. I don't think any are that great but I have found AF Magazine the most helpful for me.
Allen